40s and 50s Memories
and, on another, Ronald Fisher, who worked
at Rothamsted from 1919-1933 while founding
modern statistics and population genetics!
My Ph.D. supervisor and first mentor was Fred
Bawden, who, with his colleague Bill Pirie, had
shown in 1937 that the particles of tobacco
mosaic virus were not just protein, as had
been claimed, but contained a fixed amount
of ribonucleic acid - the first clear indication
that genes might be linked to nucleic acids,
not proteins. The interest in bee viruses led to
meeting Max Day of CSIRO, who was visiting
UK and, via him, Frank Fenner, my second
major mentor. I had first heard about Frank
and his unusually diverse department at the
Australian National University (ANU) from
my close colleague Bryan Harrison, who had
visited them in 1965. The department was
leading the world in the study of ecology and
molecular biology, and hence the evolution,
of many different animal viruses, especially
poxviruses and 'flus, and Frank was convinced
that study of virus evolution was important. So
we moved to Australia in 1966 and we've been
there ever since.
The search for the origins and evolution of
viruses has involved me in several parallel but
distinct strands of work. Not only just searching
for viruses that might provide useful clues, but
also working out how best to store virus data,
and how to derive information from that data.
At ANU I and my colleagues collected and
described novel viruses from interesting sites
throughout Australia. Many came from native
plants, also insects, even an alga, and we
helped others in such work, notably Graeme
Laver and his colleagues collecting 'flu viruses
from sea birds on Barrier Reef islands.
When I started research virus data was stored
in journals and books, and one of my first
projects was to convert Kenneth Smith's 1957
"Textbook of Plant Virus Diseases" to an edge-
punched card index to allow me to search for
hidden character correlations. Books are too
inflexible for a fast developing science like
virology, so in the 1970s, with the help of an
army of colleagues, I organised a database for
plant viruses of characters like the shape and
size of their particles, their hosts and symptoms,
etc. Many 'megapersonhours' later this has become the database of the International
Committee on the Taxonomy of Viruses.
However these data, although very useful for
pathologists and epidemiologists reveal little
about the evolutionary relationships of viruses.
That evidence comes from gene sequences
which, like languages, contain both functional
information and also differences resulting from
mutations, and these can be teased apart to
recover functional and evolutionary information.
Gene sequencing was first invented in the
1970s. In 1974 the first complete set of
genes of a virus, (coliphage phiX174), were
sequenced in Cambridge UK, and involved
a large team several years of work, whereas
the latest methods would take a few hours to
accomplish the same, and so the international
gene sequence databases are filling with mind-
boggling amounts of data, and there are too
few interested people to analyse it all! Many of
the programs for analysing the sequences only
require an ordinary home computer. So my old
age has been filled with attempts to complete
some of the studies I started several decades
ago, principally working with colleagues in
Japan over the Internet. My colleagues and I
have been able to show, for example, that one
of the most important viruses of the world's
brassica crops probably switched hosts from
wild European orchids about 1000 years ago,
when woodlands were being cut down and
agriculture was spreading to dominate the
landscape. Charles Darwin in "On the Origin
of Species" (Chapter 12) noted the particular
advantages and disadvantages of asking
evolutionary questions for the inhabitants of
"oceanic islands" like Australia, and for viruses
this is apposite. We have shown that whereas
most Australian crop viruses are recent
immigrants and entered with plants and seeds
over the past two centuries, others came from
overseas earlier, some perhaps brought to
Sahul 2,500 years ago by the Austronesians as
they explored the Pacific in outrigger canoes.
Some arrived even earlier, for example a virus
we found in a splendid alga, Chara australis, in
the Murrumbidgee River is perhaps as ancient
as Chara itself, whose fossils first appeared in
rocks at least 350 million years ago!
'Retirees' are also free to 'speak out', so it was
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